The present invention concerns an improved vapor degreaser apparatus. Specifically, the invention concerns the provision of selectively disposing a desiccator assembly within a conventional water separator of a vapor degreaser apparatus for drying and removing water from a solvent in the vapor degreaser apparatus without the heretofore required additional piping. The desiccator assembly and water separator are designed for operation of the separator with or without the desiccator assembly and for the simple replacement of the desiccator assembly.
In a conventional vapor degreasing apparatus for cleaning or drying workpieces, solvent is boiled in a sump or chamber where it is vaporized. The resulting solvent vapor is subsequently condensed, usually by means of a cooling jacket or cooling coils to minimize the escape of the vapors into the atmosphere. The condensate is returned to the boiling sump or chamber. During the condensation cycle water is introduced into the system in various ways. For example, wet workpieces or cooling coils operating below the ambient dew point will introduce water into the solvent. It is well known that the introduction of water into cleaning solvents adversely affects solvent efficacy, and chemical stability, and, therefore, removal of water is required to maintain solvent integrity. Usually the water is removed prior to the solvent condensate being returned to the degreaser boiling sump.
One standard technique of water separation comprises the use of a gravity type separator. The solvent and water mixture, in which the solvent is usually heavier than the water, is allowed to remain in a relatively quiescent chamber for a period of time until the mixture separates into two distinct layers. This occurs, typically, in several minutes, e.g. three to five minutes, after which time the water phase floats on top of the solvent phase. Upon separation of the two components the water is decanted by conventional means from the surface and the substantially dry solvent is returned to the degreaser.
In certain cases, the conventional water separation procedure is potentially detrimental because of the nature of the solvent involved. Many degreasing applications require the use of solvents which are azeotropes consisting of a base solvent, usually a fluorocarbon, and a second component, such as an alcohol. The second component is soluble in water making removal of water difficult. If a standard gravity type separator is used, the water soluble component will be removed thereby causing the solvent to change its characteristics due to the constant leaching by the water.
In such cases, a desiccant material, such as a silica gel or molecular sieve, is used to remove the water. The desiccant chemical chosen possesses the ability to dry the solvent without removing the soluble component of the solvent. Typically, the water and solvent condensate mixture is passed through an external cannister filled with the desiccant before returning the dry solvent to the degreaser.
In most of the commercially available degreasers the water separator is supplied as an integral portion of the degreaser tank. If a solvent is used which requires a desiccant for drying, then an optional desiccator assembly is required. The desiccator assembly, including the cannister, is externally mounted and piped into the degreaser unit on a semi-permanent basis.
In the present invention, the water separator and desiccant drier are combined into a single unit thereby eliminating external piping if the desiccator option is required.
The desiccant drier cannister, in a preferred embodiment, includes a threaded pipe nipple. The drain pipe leading from the separator has a corresponding threaded pipe connection for receiving the threaded nipple of the desiccator cannister. With the addition of the desiccator cannister, the solvent will automatically pass through the desiccant bed prior to being returned to the boiling sump. If the user subsequently decides to use a solvent not requiring a desiccant for drying, the desiccator assembly can be unscrewed and removed and the degreaser will then include only the conventional gravity separator. Desiccator replacement is greatly facilitated in the present vapor degreaser design.
A principal object of the present invention is, therefore, the provision of an improved vapor degreaser apparatus.
Another object of this invention is the provision of an improved degreaser apparatus obviating the requirement for external piping to add a desiccator assembly.
A further object of this invention is the provision of an improved vapor degreaser apparatus having means for adding a removable desiccator assembly in the form of a desiccator cannister.
Further and still other objects of the present invention will become more clearly apparent when the following description is read in conjunction with the accompanying drawings.